1. Field of Invention
This invention relates generally to pneumatic play balls, and more particularly to a light weight play ball whose inner inflatable bladder is an ordinary rubber balloon, yet the ball is of exceptional strength so that it may be subjected to rough handling.
2. Status of Prior Art
A standard football is of oval shape and is made of an inflatable, high strength inner bladder and an outer casing formed of heavy leather, rubber or flexible plastic material. The bladder is provided with a valve so that it can be inflated with air, the valve automatically closing to retain the air in the bladder. Made in a similar fashion are spherical soccer balls, volley balls and basketballs. In these standard balls, the bladder is molded to assume, when inflated, the same shape as the outer casing.
In the process of play, standard sports play balls of the pneumatic type are tossed, kicked and bounced, the balls being capable of withstanding very rough handling. While such balls are not regarded by adults as unduly heavy, they represent an intolerable load to a young child. Moreover, a standard inflatable athletic ball tends to produce a "hand sting." This effect arises when the ball which has a hard casing is caught by the bare hands while moving at high velocity.
While small children are attracted to conventional athletic balls and enjoy watching adults play soccer, football and other ball games, in the hands of a small child these athletic balls are heavy and dangerous, especially in indoor play. The standard inflated athletic ball has a relatively large diameter and a smooth, hard outer casing which makes it very difficult for a small child to grasp, throw and catch.
The toy and game industry has long recognized the need for a lighter, softer and potentially less dangerous ball for young children. Thus, balls in various shapes and sizes are not commercially available which are molded of polyurethane foam material and other light-weight compressible plastics. While such balls are safe in the hands of pre-school children and will inflict no harm even if the ball is hurled toward the body of another child, they fail in many respects to satisfy the typical child's desire for a ball that looks like a real athletic ball of the type used by adults, that is bouncy and is not an unconvincing substitute for a regulation ball.
Thus the soft play balls described in the Wexler U.S. Pat. No. 4,738,450 are provided with an outer casing an an inner core of shredded fibrous material. But such balls, while they look like a standard athletic ball, lack pneumatic characteristics and do not bounce.
Another practical drawback of a conventional inflatable play ball is that it cannot readily be collapsed, flattened out and folded to form a compact package. If, therefore, one wishes to take a conventional play ball to a park or beach for use by children, one must carry the ball in its inflated condition. This presents a problem if the parents accompanying the children are already loaded with folding chairs, picnic baskets and other articles appropriate to the occasion.
My prior U.S. Pat. No. 4,834,382 (Spector) discloses a pneumatic play ball that has the configuration and appearance of a standard pneumatic athletic ball, such as a regulation basketball. Yet the patented ball is much lighter and therefore in the hands of young children is safer to play with, especially in indoor play. Despite its light weight, the ball is exceptionally strong. And when not in use, the Spector ball may be collapsed into a highly compact form.
The Spector ball is constituted by an outer casing and an inner inflatable bladder. The outer casing is formed by contoured segments of high strength, non-stretchable fabric material stitched together to define, when the casing is fully expanded, a play ball of the desired shape and size, such as a football or soccer ball. The inner bladder is a conventional thin-skin rubber balloon whose stem initially projects through an opening in the casing which is provided with a closure.
The stem, after the balloon is inflated with air so that it conforms to the casing, is then tied into a knot to retain the air, the tied stem being pushed into the casing and being concealed by the closure. Because the balloon is fully encased, no portion thereof can be extruded from the casing when the ball is bounced and the internal pressure within the balloon is increased.
Thus when the Spector ball is assembled, no portion of the inflated balloon therein is exposed, for the balloon, including its stem, is then enclosed by the outer casing. An un-encased rubber balloon has little strength and is easily burst by applying external pressure to one region thereof, as a result of which the unpressed region is caused to stretch to its bursting point. But when the inflated balloon is confined within a non-stretchable fabric casing, even though the balloon, per se, is inherently weak, because of the casing does not permit any region of the balloon to further expand beyond its existing degree of expansion, the balloon will not burst even if a heavy adult sits on the ball or the ball is given a hard kick.
The reason the Spector ball has high bounce characteristics is that its internal air pressure is much higher than a conventional beach ball made of a non-stretchable plastic film. In the conventional beach ball, it takes little pressure to blow it up, for the plastic sphere offers little resistance to expansion until it is fully inflated, at which point since the material is non-stretchable, it cannot be further inflated. But with a stretchable rubber balloon, it takes much more air pressure to stretch the rubber from its initial state to its stretched and inflated state, as a consequence of which the internal air pressure in the Spector ball is much higher than in a conventional beach ball. The bounce characteristics of a pneumatic ball is a function of its internal air pressure. Thus in a standard tennis ball, when the internal air pressure is reduced as a result of gradual air leakage, the ball becomes "dead" and then has insufficient bounce for the game.
In the Spector ball, the opening in the casing must be large enough to permit insertion therethrough of an uninflated rubber balloon, and also to permit withdrawal from the casing of the balloon after it has been deflated by puncturing the balloon. While this makes it necessary, in order to reuse the ball, to insert therein a fresh balloon, the cost of a typical rubber balloon lies in the penny range.
The Spector patent discloses an opening in the casing and a separate closure therefor such as a zipper or Velcro fastener. Closures of these types need only add to the cost of fabricating the casing but they also have practical drawbacks. Thus a Velcro fastener necessarily protrudes somewhat above the surface of the casing, while in the case of a zipper, its pull tag will dangle from the casing.
The following patents disclose pneumatic articles which make use of rubber balloons and are therefore of prior art interest: U.S. Pat. Nos. Hendershott, 4,917,382; Murphy, 1,558,200; Hendry, 1,383,115.